A conventional image pickup device, which increases the resolution of a base image by weighting a plurality of reference images when the resolution of a photographed image is enhanced, is known (JP2006-140886A, page 1, FIGS. 1 and 2). In this image pickup device, a larger weighting coefficient is applied to a reference image that is temporally closer to the base image, and a smaller weighting coefficient is applied to a reference image that is temporally farther from the base image.